The present invention relates generally to a film viewer and more particularly to apparatus for holding and back illuminating X-ray film.
Medical X-ray films usually are examined by placing them on the viewing screen of a device commonly referred to as an illuminator or X-ray viewer. Most conventional X-ray viewing boxes have a fluorescent illumination source within the box and a standard viewing size screen of 14 inches by 17 inches. Some of the viewing boxes have a single 14 by 17 panel, and others have multiple such panels. Generally when such multiple panels are provided, they are provided in a side-by-side series with means for illuminating each panel independently of the next. Other prior art viewing boxes not only have 14 by 17 inch multiple panels laid side by side, but in addition provide a second series of such panels above or below the first series. For example, see the X-ray Viewer disclosed in U.S. Pat. No. 3,201,883 issued on Aug. 24, 1965 to S. L. Schleisner-Meyer.
However, there is currently a widespread use of smaller X-ray film measuring 8 inches by 10 inches for use in ultrasound, nuclear medicine; and CT films smaller than 14 inches by 17 inches are frequently used for other examinations. 70 mm and 100 mm films are also popular.
Conventional X-ray film viewing apparatus are ineffective and inefficient when using smaller films because there is no way to hold two 8 inch by 10 inch films on a 14 inch by 17 inch view box illumination panel and still having capabilities to use the box for reading 14 inch by 17 inch chest X-rays when small films are not being viewed.
When a film smaller than 14 inches by 17 inches is to be examined, for example, on a 14 inch by 17 inch viewing screen, the film is retained in a conventional manner on the surface of the viewing screen by pushing the upper edge on the film under a spring-loaded clip located along the top edge of the viewing screen. This leaves the bottom portion of the screen surrounding the film or films illuminated and the resulting glare detracts from the visual perception of the person trying to study the film and creates considerable eye strain, particularly if viewing is done over a long period of time.
Both of these aforementioned problems have been solved in one form by the self-masking X-ray viewing apparatus disclosed in U.S. Pat. No. 4,004,360 issued Jan. 25, 1977 to K. C. Hammond. This particular prior art apparatus discloses a relatively complex viewing device which does indeed eliminate unnecessary glare and further at the same time permits viewing of film smaller than 14 inches by 17 inches. However, a problem remains in that this prior art device must be independently manufactured and accordingly provides no means for adapting existing X-ray film viewing apparatus to accomplish these results of eliminating glare and providing a means for viewing multiple smaller X-ray films on a conventional 14 inch by 17 inch illumination screen already in use or on the market.
As illustrated in U.S. Pat. No. 2,436,162 issued Feb. 17, 1948 to F. J. Cadenas and U.S. Pat. No. 1,988,654 issued Jan. 22, 1935 to T. T. Haag, other prior art X-ray film viewers have eliminated the problem of glare by the use of masking plates or drawable shades to block off that portion of the viewing screen which is not illuminating an X-ray film. However, such film viewers do not provide means to adapt a single or multiple 14 inch by 17 inch viewing screen so that each such panel may be fully utilized by placing a number of smaller X-ray films over its entire viewing area while further providing means to mask off unwanted surrounding glare, and thereafter providing means to readily re-adapt the viewing box to receive full sized 14 inch by 17 inch X-rays for viewing.
It is a principal object of the present invention to provide an X-ray viewing apparatus which eliminates these aforementioned disadvantages, and in so doing provide a means to readily adapt existing viewing apparatus on the market to do so.